1. Field of the Invention
The present invention relates to an operational control apparatus and method for a video cassette recorder (hereinafter referred to as "VCR") utilizing a shuttle ring, and more particularly to an operational mode control apparatus and method for a VCR which can control all operations of the VCR by utilizing a shuttle ring as well as improve the structure of the shuttle ring
2. Description of the Prior Art
In a conventional VCR with a shuttle ring, all operation modes related to reproduction, such as high speed search mode, normal speed reproduction mode, low speed reproduction mode, still mode, etc., can be controlled by operating the shuttle ring.
As shown in FIG. 1, a conventional operational control apparatus for a VCR with a shuttle ring comprises a shuttle section 1 including a shuttle ring and generating a digital signal for mode control in accordance with a rotational angle of the shuttle ring, a syscon microcomputer 5 for determining operational mode by the digital signal outputted from shuttle section 1 and providing a mode control signal to perform the determined operational mode, a key matrix 2 composed of a plurality of keys for selecting operational modes of a VCR, a timer microcomputer 3, and a display section 4 for displaying the selected mode.
In the conventional apparatus constructed as above, a code signal in accordance with a rotational angle of the shuttle ring is generated from shuttle section 1 and is supplied to syscon microcomputer 5. Also, a key signal for selecting the operational mode of a VCR is generated from key matrix 2 and is also supplied to syscon microcomputer 5 through timer microcomputer 3. Display section 4 is connected to timer microcomputer 3 in order to visually display the present mode selected by key matrix 2 or shuttle section 1.
However, in such a conventional apparatus, shuttle section 1 can control only modes related to reproduction, so that key matrix 2 should be provided together with shuttle section 1 in order to control all operational modes of a VCR.
FIG.2 shows the structure of shuttle section 1 in the conventional apparatus of FIG. 1. Referring to FIG. 2, the shuttle section includes a shuttle ring 1a, being rotated by a user, to provide digital signals DS1 to DS4 in accordance with its rotational angle. Shuttle ring 1a has a substrate 1b having contact patterns formed thereon and generates digital signals DS1 to DS4 by selectively supplying B+ supply voltage through a resistor R to the contacts, respectively in accordance with the rotational angle thereof. That is, if the rotational angle .theta. of shuttle ring 1a is in a region between 0.degree. and 20.degree. shuttle ring 1a provides digital signals of "1000" (where, 1 is "high" level and 0 is "low" level), and if 20.degree..ltoreq..theta.&lt;40.degree., "1010" is outputted.
The operational of the conventional control apparatus constructed as above will be explained with reference to FIG. 1 to FIG.4.
When the B+ supply voltage is applied, shuttle ring 1a provides to syscon microcomputer 5 digital signal DS1 to DS4, which varies as the user rotates shuttle ring 1a. Referring to FIG. 3, if a video tape is safely placed in a deck and mode selection can be performed by shuttle ring 1a, syscon microcomputer 5 determines the rotational angle of shuttle ring 1a according to the signal DS1 to DS4 received from shuttle section 1 as shuttle ring la rotates and provides a mode control signal for performing an operational mode corresponding to the determined rotational angle.
For example, assume that shuttle ring 1a rotates clockwise, if 0.degree..ltoreq..theta.&lt;20.degree., then still mode is performed, and if 20.degree..ltoreq..theta.&lt;40.degree., then low speed reproduction is performed. After that, as shuttle ring 1 rotates clockwise further, forward reproduction is performed at a higher speed.
Meanwhile, assume that shuttle ring 1a rotates counterclockwise, if -20.degree..ltoreq..theta.&lt;0.degree., then reverse low speed reproduction mode is performed, and if -40.degree..ltoreq..theta.&lt;-20.degree., then reverse normal speed reproduction mode is performed. After that, as shuttle ring 1 rotates counterclockwise further, reverse reproduction is performed at a higher speed.
In this state, if a user takes his hand off shuttle ring 1a, shuttle ring 1a is restored to its original position of 0.degree. and still mode is performed. Stop mode can be performed only when a stop key is entered through key matrix 2.
However, since the shuttle ring in the conventional apparatus should employ a substrate patterned by specific contacts with four or more lines, the structure thereof becomes complex and the manufacturing cost increases.